1. Field of the Invention
The present invention relates to a substrate, and more specifically, to a substrate having a number of electrodes formed on a base to protrude and a semiconductor device using the substrate.
Priority is claimed on Japanese Patent Application No. 2012-075927, filed Mar. 29, 2012, the content of which is incorporated herein by reference.
2. Description of Related Art
A smaller high-performance semiconductor device has been required for a small highly functional system, and a stacked semiconductor device formed by bonding wafers having a number of microelectrodes formed therein has been studied.
In such a stacked semiconductor device, it is necessary to apply a load to wafers that are bases in order to electrically connect the electrodes, but a required load increases with the number of electrodes. For example, when electrodes having a diameter of about 10 μm are formed in an entire surface of a wafer of 8 inches (23.2 cm), the number of electrodes is hundreds of millions and a load required for bonding is several tons. If such a load is concentrated on specific electrodes, the electrodes or the wafer may be damaged.
Generally, it is said that if electrodes are formed as a two-dimensional array in a region having a predetermined area, there is a tendency for a greater stress to be applied to electrodes located in a peripheral portion of the two-dimensional array at the time of bonding of wafers. Presence of a region in which there are no other electrodes around the electrodes in the peripheral portion and difficulty in sharing a load in the region with the other electrodes may be considered factors contributing to this tendency.
A method of forming dummy electrodes in close contact with a semiconductor substrate in a peripheral portion of the semiconductor substrate with a higher distribution density than a distribution density of electrodes in a circuit region and bonding the dummy electrodes to each other in the semiconductor substrates has been proposed in Japanese Unexamined Patent Application, First Publication No, 2009-158764.